- Active tuberculosis (TB) within the previous 3 years regardless of treatment history for TB. Participants with a known positive purified protein derivative (PPD) or positive Quantiferon assay will not be eligible for the study unless they have completed treatment for latent TB and have a negative chest x‐ray at the time of enrollment. PPD testing or Quantiferon testing done within 52 weeks before transplant is acceptable as long as there is documentation of the results. Prior recipients of a Bacille Calmette‐Guérin vaccination (BCG) are not exempt.